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#20
by
butters
on 23 Sep, 2014 20:32
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So this is an unsolicited offer from ATK which ULA will place in the round file. Thanks but no thanks.
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#21
by
edkyle99
on 23 Sep, 2014 20:37
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So this is an unsolicited offer from ATK which ULA will place in the round file. Thanks but no thanks.
It is self-described as a "Solution to U.S. Air Force's RD-180 Replacement Request", so it isn't clear to me that this was an offer directly to United Launch Alliance. It may have been a response to the following RFI.
https://www.fbo.gov/?s=opportunity&mode=form&id=6900cbd5088703bad8a5a5e6862e7a55&tab=core&_cview=0Indeed, ULA's Blue Origin BE-4 announcement may essentially represent its response to the same RFI.
- Ed Kyle
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#22
by
edkyle99
on 23 Sep, 2014 20:47
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In flight, not predetermined. Each solid would have to be made per flight mission then?
No. Shuttle SRBs, Titan SRMs, etc, had fixed throttle profiles even though the payload masses and insertion orbits varied. A generic profile can be created that covers a wide range of missions. When it comes to solids, customization was most commonly limited to the final stage motors, like the IUS motors, etc. That won't be needed if a liquid upper stage is used.
- Ed Kyle
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#23
by
sdsds
on 23 Sep, 2014 20:50
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Can't fly CST-100 on it unless all the vibration dampening mechanisms are included in the Atlas re-design that were worked out for Ares-I.
Yes. Thus this bit from the press release:
New solid rocket motor technology has the capability to provide a smooth lift for payloads, which is especially important when launching critical payloads, sensitive satellites and crews.(Emphasis added by me.)
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#24
by
StarLifter
on 23 Sep, 2014 20:54
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I believe that for Antares to use a solid ATK first stage. There would be problems with local state authorities do to the close proximity, only a few miles north, of the heavy populated Chincoteague island resort?
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#25
by
strangequark
on 23 Sep, 2014 21:18
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Can't fly CST-100 on it unless all the vibration dampening mechanisms are included in the Atlas re-design that were worked out for Ares-I.
Bear in mind that one of the issues with Ares I thrust oscillation was that you have shedding vortices due to the burning happening down in the gap between each segment. Not an issue if you don't do a segmented motor.
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#26
by
Space Ghost 1962
on 23 Sep, 2014 21:19
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I think this is just for PR and Congressional sabre rattling.
I find it humorous to imagine the two use cases for RD-180 "replacement" - stacking solids in the Atlas VIB or theoretically a impossible to transport monolithic with an enormous crane, or the Antares HIB trying to integrate and load either way onto the transporter such masses. You'd need very different safety protocols, suits, ... The transporters couldn't take the weight, and the pad infrastructure would all need to be massively reworked. Might as well start from scratch.
Compare this to what Sowers said was like a Atlas II/III transition, where all you are doing is loading a 5M stage into new cutouts on the VIB just like with the existing 4M stage, using the same crane. Night and day difference.
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#27
by
Hauerg
on 23 Sep, 2014 21:29
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Sounds a bit like Liberty 2.0...
The undead strikes again.
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#28
by
Lobo
on 24 Sep, 2014 00:18
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Sounds a bit like Liberty 2.0...
The undead strikes again.
I don't think it's un reasonable or unfeasible to have a large solid motor on an ELV of the size of the standard Atlas Core. We're not talking about a huge 5-segmented stick here. More like two 3.71m wide monolithic motors stacked to replace the Atlas core with two solid stages. Obviously ArianeSpace is looking at doing basically this with Ariane 6. On a smaller scale its worked with Minuteman ICBM's, Athena, and Taurus fine.
So just because the Stick was a Kludge doesn't mean any ATK solid motor is.
That said, it would seem that ULA has already found a partner to help create a new LV which will presumably replace Atlas V all together in the future...and perhaps Delta IV as well. While that's being developed, ULA will use it's existing stock of RD-180's as well as try to procure additional engines if their manifest requires more engines than are currently under contract prior to the new LNG LV being ready. So there would seem to be no reason for ULA to seriously consider a solid booster replacement for Altas. This proposal was probably in the works before the news came out about ULA's partnership with BO. And it could be that they figure they could lobby Congress to get USAF/DoD to require ULA to go with a US-made solid booster replacement for Atlas. Which perhaps had a little better chance before the announcement of a new LV with a US-made liquid engine. I'm thinking that was the case with AJR's AR-1 as well. If USAF/DoD tells ULA to supply a solid powered or AR-1 powered Atlas V for their payloads, and pony up the money for it, obviously ULA would likely do just that.
The parnership with BO would seem to perhaps end-around that scenario now, and allow ULA more flexibility on how they proceed. Although I would think USAF/DoD could still threaten to pull their subsidies if ULA isn't supplying them what they want. But since the BE-4 is a US made engine, I don't know why they'd do that. But I don't understand the intracacies of the policies between USAF/DoD and ULA. Jim I'm sure can clarify that.
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#29
by
arachnitect
on 24 Sep, 2014 00:45
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Wonder if this is the same product they were pitching to Orbital for Antares
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#30
by
TrevorMonty
on 24 Sep, 2014 00:48
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Even though ULA are going with a domestic engine ie BE4, DOD are still seriously considering paying for development of another engine. SpaceX gives them LV redundancy if the supply of BE4 was ever cutoff.
For this redundant engine to be of any use it has to be fitted to a LV. Does DOD also plan to fund this redundant LV?
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#31
by
Space Ghost 1962
on 24 Sep, 2014 00:53
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Any solid that does the work of the RD-180 liquid stage, will at least take the weight of a fully loaded with propellant stage. The cranes and structure won't take it.
Actually, it must be heavier for various significant reasons. Yes you can divide it in two/three, but then you add issues you don't want to add - like staging events/igniters/gimbals/TO mitigation, that now must factor in 2-3x, and the risks that go with them.
Not to mention the acoustics, the flame trench, load paths. It wasn't designed with those in mind.
The pad had Titan 4 SRMU's on it before. The flame trench in effect took worse. The pad had the ability to support heavy loads in the past. Is it modifiable back to support those acoustics? Is the VIB too close for the surface wave? Were there any considerations to strap on SRB overpressure events where they modelled something similar?
Compare this to a 1.3x heavier stage than before.
Now, you can stack these things at a solids pad in little development time. Hard part would be the hydrolox and payload support.
If it was an all solid vehicle, you could bring it online extremely fast, and scale up to meet demand. But that's not Atlas.
This was a large part of why PPH didn't trade well - new all up pad. And the fact that the modularity didn't span far enough. And that it didn't have enough flight frequency for the economics to work. And that it didn't last long enough to get the economics to work.
edit:
Jim got me.
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#32
by
Jim
on 24 Sep, 2014 01:03
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Not to mention the acoustics, the flame trench, load paths. It wasn't designed with those in mind.
Actually, yes it was. Titan facilities are being used, and some former Titan payloads were being flown
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#33
by
wannamoonbase
on 24 Sep, 2014 01:43
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I'm curious about the specifics, but it does feel like a "square peg in a round hole" kind of solution.
ATK provides decent products for people with square holes.
They are masters of lobbing these less than optimal ideas out. But US politics being what it is, sometimes they get lucky and provide a sub-optimal solution for 30 years of shuttle flights.
Solids have a place, but liquids appear to be setting up to win this round.
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#34
by
mr. mark
on 24 Sep, 2014 02:22
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With all this swapping and switching maybe Boeing will take a serious look at having Falcon 9 as their FIRST choice for CST-100.
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#35
by
Kabloona
on 24 Sep, 2014 02:32
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Even though ULA are going with a domestic engine ie BE4, DOD are still seriously considering paying for development of another engine. SpaceX gives them LV redundancy if the supply of BE4 was ever cutoff.
For this redundant engine to be of any use it has to be fitted to a LV. Does DOD also plan to fund this redundant LV?
The DoD doesn't need to fund more LV's, given the proposed evolution of Atlas/Delta with BE-4 and the prospect of F9 being certified soon and FH coming down the pike.
But maybe the AR-1 survives on the back burner as an alternate engine for ULA with some DoD funding in case BE-4 development runs into trouble, and/or with NASA funding as an eventual SLS engine.
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#36
by
arachnitect
on 24 Sep, 2014 02:39
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With all this swapping and switching maybe Boeing will take a serious look at having Falcon 9 as their FIRST choice for CST-100.
CST will be flying years before any of the talked about changes are implemented.
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#37
by
daveklingler
on 24 Sep, 2014 03:47
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My cynical predictions:
The money will be there whether or not ULA needs or wants it.
Either PWR or ATK or both will receive money for development.
At least one "replacement for the RD-180" will be developed and later shelved. Too many people have smelled green for the funding process to stop now. And that, folks, is politics.
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#38
by
Proponent
on 24 Sep, 2014 09:43
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What would you prefer BE-4 or ATK solid for crewed CST-100 flights?
Other things being equal, I'd prefer the BE-4, because liquids' failure modes tend to be more benign (i.e., shutdown instead of kaboom with no warning). For crew launch, either CST-100's escape capabilities would have to be beefed up quite a bit or a semi-graceful shutdown mechanism would have to be built into the solids.
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#39
by
daveklingler
on 24 Sep, 2014 13:40
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Even though ULA are going with a domestic engine ie BE4, DOD are still seriously considering paying for development of another engine. SpaceX gives them LV redundancy if the supply of BE4 was ever cutoff.
For this redundant engine to be of any use it has to be fitted to a LV. Does DOD also plan to fund this redundant LV?
The DoD doesn't need to fund more LV's, given the proposed evolution of Atlas/Delta with BE-4 and the prospect of F9 being certified soon and FH coming down the pike.
But maybe the AR-1 survives on the back burner as an alternate engine for ULA with some DoD funding in case BE-4 development runs into trouble, and/or with NASA funding as an eventual SLS engine.
That brings up an interesting question. Is the choice ultimately ULA's or the Air Force's? To wit, can OATK lobby the Air Force to order a competition?